This invention relates generally to a method for joining bodily tissue in surgical applications and wound repair, and more particularly to a surgical suturing method for joining bodily tissue using a suture having a plurality of barbs which permit the suture to be pulled through the tissue in one direction but resisting movement of the suture relative to the tissue in the opposite direction.
Surgical or accidental wounds are typically closed with a length of filament introduced into the tissue by a sharp metal needle attached to one end of the filament. This device is known as a “suture”. Sutures are used to make “stitches” to close the wound for holding tissues together for healing and regrowth. Sutures are used in surgical procedures for wound closure, to close the skin in plastic surgery, to secure damaged or severed tendons, muscles or other internal tissues, and in microsurgery on nerves and blood vessels. Generally, the suture needle is caused to penetrate and pass through the tissue pulling the suture through the tissue. The opposing faces of the tissue are then moved together, the needle is removed, and the ends of the suture are tied in a knot. The suture forms a loop as the knot is tied. The knotting procedure allows the tension on the filament to be adjusted to accommodate the particular tissue being sutured and control of approximation, occlusion, attachment or other conditions of the tissue. The ability to control tension is extremely important regardless of the type of surgical procedure being performed.
Suturing is a time-consuming part of most surgical procedures, particularly in microsurgery and endoscopic surgery where there is insufficient space to properly manipulate the suture. Loop sutures can leave scars where they penetrate skin. For adequate closure of some wounds, the suture material must be of a high tensile strength and thus a large diameter thereby increasing scarring. The loop suture also constricts blood flow to the tissue it surrounds, promoting necrosis of the wound margins which compromises healing and increases infection risks. Further, the tissue is distorted as it is secured by the suture loop due to excess tension on the knots. Localized tensions from the knots are the culprit for scar formation. The bulk of the knots are also an impediment to wound healing in internal applications.
Alternatives to conventional sutures for wound closure are known, including fasteners such as staples, clips, tacks, clamps and the like. The fasteners are usually positioned transversely across a wound for joining or approximating each side of adjacent tissue layers laterally. Fasteners have relatively high strength and save time, but are not as accurate as sutures and are bulky and may be painful to remove. Fasteners are also generally unsuitable for deeper layers of tissue. Moreover, fasteners do not provide the advantage of adjustable tension obtained by the knotting of a length of suture material.
Surface adhesive tapes and glues are often used on skin to hold small wounds closed to permit healing. However, these products have relatively low tensile strength and are not useful in many situations.
Other techniques proposed include electrical coagulation and lasers. However, no acceptable alternative has been found which offers the advantages of suturing and tying in most surgical procedures.
One possible alternative is a barbed suture. A barbed suture includes an elongated body having one or more spaced barbs projecting from the surface of the body along the length of the body. The barbs are configured to allow passage of the suture in one direction through tissue but resist movement of the suture relative to the tissue in the opposite direction. In wound closure, a barbed suture is passed through tissue at each of the opposed sides of a wound. The wound is closed by pushing the sides of the wound together with the barbs maintaining the sutures in place and resisting movement of the tissue away from this position. The advantage of using barbed sutures is the ability to put tension in the tissue with less slippage of the suture in the wound. The barbed suture spreads out the holding forces evenly thereby significantly reducing tissue distortion. Since knots do not have to be tied, there is a time savings and the elimination of suture knots improves cosmetic effects and promotes wound healing. Barbed sutures also allow better apposition of tissue since the incised or insulted tissues are brought together and secured with almost no movement immediately. Unlike the conventional suturing method wherein tension is applied by pulling on the end of the suture after placement, barbed sutures permit tissue to be approximated and held snug during suturing. This is especially advantageous in closing long incisions. The result is better healing when the tissue levels are harmoniously matched as the cosmetic effect is more pronounced at skin level. Moreover, if there is an accidental breakage of the barbed suture, the wound is minimally disturbed. With conventional sutures, dehiscence would occur.
Despite the advantages offered by barbed sutures, the tensile strength of a barbed suture is less than a loop suture of equivalent size. This is due to the reduced tensile strength resulting from imparting the barb structure onto the body of the suture, which reduces its effective diameter. This limitation is not significant since larger barbed sutures with greater tensile strength can be utilized. However, the conventional methods for introducing barbed sutures into tissue still do not exhibit the same biomechanical performance of looped sutures.
For the foregoing reasons there is a need for a suturing method for joining tissue in surgical applications and wound repair which is efficient and expedites the surgical procedure. Ideally, the new method allows a surgeon to suture in an efficient manner to quickly approximate tissue with appropriate tension. The new method should preserve blood flow, improve wound healing strength, prevent distortion of the tissue and minimize scarring. The method should also incorporate the self-retaining benefits of the barbed suture with the holding power of conventional suturing methods. A particularly useful method would be utilized in surgical applications where space is limited such as microsurgery, endoscopic surgery, or arthroscopic surgery.